1. Field
The present disclosure relates generally to aircraft and, in particular, to inert gas generation systems for aircraft. Still more particularly, the present disclosure relates to a method and apparatus for controlling operation in an inert gas generation system for aircraft.
2. Background
Many aircraft have inert gas generation systems. An inert gas generation system may be used to render a fuel tank in an aircraft substantially inert. Fuel tanks in an aircraft may have a space above the fuel in which fuel vapors may be present. This space in the fuel tank is referred to as an ullage.
The inert gas generation system is employed to reduce a possibility of combustion within this space in a fuel tank. The inert gas generation system may reduce the oxygen content in these spaces below a threshold needed for combustion. Without sufficient oxygen, combustibility of fuel vapors in these locations is unlikely.
The inert gas generation system introduces an inert gas into the ullage in the fuel tank. This inert gas may be, for example, nitrogen, nitrogen enriched air, carbon dioxide, and other types of inert gases.
An inert gas generation system may employ air separation modules to generate the inert gas. For example, an air separation module may be configured to generate nitrogen enriched air from air that is sent into the air separation module. This nitrogen enriched air is then sent into the fuel tank.
The operation of the inert gas generation system may increase fuel costs more than desired to operate the aircraft. Further, continual use of the inert gas generation system during operation of the aircraft may increase maintenance needed for the inert gas generation system.
Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above as well as possibly other issues.